The chief executive of Ryanair has attacked the UK government-backed rescue of regional airline Flybe, joining industry heavyweight Willie Walsh in opposing state help for a private company. 

Ryanair CEO Michael O'Leary said he had written to UK finance minister Sajid Javid, calling on him to extend the same benefits to his airline as it has given to Flybe. 

Flybe was kept afloat this week after its shareholders agreed to invest more money alongside a UK government support plan, but details of that support have not been made public. 

Media reports say it involves the deferral of a passenger tax (APD) bill and a potential government loan. 

The UK government has defended the rescue deal and said it is fully compliant with state aid rules. 

Willie Walsh, the head of the parent company of Aer Lingus and British Airways, has complained about the rescue and filed a complaint with the EU saying that help for Flybe constituted a breach of state aid rules. 

Michael O'Leary said Flybe should not be singled out for help. 

"This government bailout of the billionaire-owned Flybe is in breach of both competition and state aid laws," he said in a statement, adding that any holiday Flybe had been given from APD should be extended across the industry.

Flybe is owned by Connect Airways, a consortium created by Virgin Atlantic, Stobart Group and investment adviser Cyrus Capital.

In the letter to Sajid Javid, Ryanair said that the Flybe business model is neither profitable nor viable and the airline has lurched from failure to failure repeatedly over the last 20 years.

"The reason why Flybe isn't viable is because it cannot compete with lower fare services from UK regional airports on domestic and EU routes provided by Ryanair, Easyjet, BA and others," Ryanair's chief executive Michael O'Leary said.

Mr O'Leary also said that Flybe can not compete with lower cost road and rail alternatives on many smaller UK domestic routes.  

"If Flybe fails (as it undoubtedly will once this government subsidy ends) then Ryanair, Easyjet, BA and others will step in and provide lower fare flights from the UK regional airports, as we already have to make up for the recent failure of Thomas Cook Airways," Mr O'Leary added.